Tamara E. Carver

In vivo precision of the GE iDXA for the assessment of total body composition and fat distribution in severely obese patients

To evaluate the precision of the iDXA for total body composition and fat distribution measurements in severely obese patients.

Validity and reliability of Fitbit activity monitors compared to ActiGraph GT3X+ with female adults in a free-living environment

OBJECTIVES Inexpensive activity monitors have recently gained popularity with the general public. Researchers have evaluated these consumer-based monitors in laboratory-conditions. Given the current wide-spread consumer use of these devices, it is important to ensure users are attaining accurate information compared to previously validated measures. This study investigates the accuracy of Fitbit One and Flex activity monitors in measuring steps, sedentary time, and time spent in light, moderate, and vigorous intensity activities with ActiGraph GT3X+ with female adults in free-living conditions. DESIGN Cross-sectional study. METHODS Twenty-two women, 21.23±1.63 years, BMI: 22.35±2.34kg/m2 wore two Fitbit Ones (bra and waist), one Fitbit Flex on the wrist, and one ActiGraph GT3X+ on the waist for seven-consecutive days. Repeated measures ANOVA was used to explore differences in steps, sedentary time, and time spent in light, moderate and vigorous intensity activities among the four devices. RESULTS No differences were found in number of steps recorded across the four devices. Fitbit One, waist and bra, overestimated time spent in light intensity activities. Fitbit One (waist) and Fitbit Flex overestimated time spent in moderate intensity activities. Fitbit One, waist and bra, and Fitbit Flex overestimated time spent in vigorous intensity activities. All Fitbit activity monitors overestimated MVPA and underestimated sedentary time compared to the ActiGraph. CONCLUSIONS Regardless of wear-location all Fitbit devices provide similar activity monitoring and users can wear the devices wherever best accommodates their lifestyle or needs. Users should not rely solely on these monitors when tracking vigorous and MVPA activities.

Precision of the iDXA for visceral adipose tissue measurement in severely obese patients.

UNLABELLED A new measurement tool, the automated software CoreScan, for the GE Lunar iDXA, has been validated for measuring visceral adipose tissue (VAT) against computed tomography in normal-weight populations. However, no study has evaluated the precision of CoreScan in measuring VAT among severely obese patients. PURPOSE The purpose of the study was to evaluate the precision of CoreScan for VAT measurements in severely obese adults (body mass index > 40 kg·m(-2)). METHODS A total of 55 obese participants with a mean age of 46 ± 11 yr, body mass index of 49 ± 6 kg·m(-2), and body mass of 137.3 ± 21.3 kg took part in this study. Two consecutive iDXA scans with repositioning of the total body were conducted for each participant. The coefficient of variation, the root-mean-square averages of SD of repeated measurements, the corresponding 95% least significant change, and intraclass correlations were calculated. RESULTS Precision error was 8.77% (percent coefficient of variation), with a root-mean-square SD of 0.294 kg and an intraclass correlation of 0.96. Bland-Altman plots demonstrated a mean precision bias of -0.08 ± 0.41 kg, giving a coefficient of repeatability of 0.82 kg and a bias range of -0.890 to 0.725 kg. CONCLUSIONS When interpreting VAT results with the iDXA in severely obese populations, clinicians should be aware of the precision error for this important clinical parameter.

Physical activity and sitting time in bariatric surgery patients 1-16 years post-surgery.

Physical activity (PA) is an important adjunct to bariatric surgery in the treatment of severe obesity; however, patient PA levels prior to and in the short‐term following surgery are usually low. Scarce data exist describing PA and sedentary behaviours in the long term following surgery. The objectives were to describe PA and sitting time in bariatric patients 1–16 years post‐surgery and assess their associations with patient, surgery and weight‐loss characteristics. A total of 398 bariatric patients (73% female; mean age 47 ± 11 years, mean 6 ± 4 years since surgery) completed a telephone questionnaire. Patients reported moderate‐to‐vigorous PA (MVPA: # sessions week−1 ≥30 min), sitting time (h d−1) and change in PA and sitting time vs. pre‐surgery (more/same/less). Associations with patient, surgery and weight‐loss characteristics were assessed. Only 53% of patients reported ≥1 session week−1 MVPA, mean sitting time was 7 ± 4 h d−1, 74% of patients reported more PA and 53% reported less sitting, now vs. pre‐surgery. Age, sex, smoking status, pre‐surgery body mass index, time‐since‐surgery and percent excess weight lost were significantly associated with PA and/or sitting outcomes. Patients currently experiencing ≥50% excess weight loss had over three times the odds of reporting ≥1 session week−1 MVPA (odds ratio [95% confidence interval] 3.28 [1.57, 6.89]) and almost four times greater odds of reporting ‘more’ PA vs. pre‐surgery (3.78 [2.15, 6.62]) compared with their less successful counterparts. Results point to low PA and high sedentariness among bariatric patients in the long‐term following surgery, associated with several characteristics. Associations with long‐term weight management highlight the need for tailored interventions to promote active living in this patient population.

Pilot investigation to evaluate changes in exercise capacity following a prehabilitation intervention among seriously obese patients awaiting bariatric surgery

| 149 Introduction: Alberta Health Services (AHS), launched in 2009, brings together twelve previous provincial health entities. In 2010, work was undertaken within AHS to develop a comprehensive provincial plan to combat obesity. The plan crosses the care continuum and outlines strategies for provincial service coordination, health promotion and prevention, and primary and specialty care. The process has highlighted both opportunities and challenges for system collaboration to strategically address obesity. Key learnings will inform and improve future provincial planning for obesity and other planning that impacts obesity. This presentation describes the process of plan development, focusing on key learnings. Methods: A provincial steering committee, working groups, and project team were established to guide plan development. Plan content was gathered by multiple methods and involved stakeholders across AHS portfolios with responsibilities for strategy, service delivery, and organizational infrastructure. Plan development was supported by ongoing input from medical and administrative leadership, and documented through various meeting minutes, as well as archiving of draft documents and email correspondence. The project team engaged in a formal debriefing to document key learnings for future work, including completion of a project report. results: The plan was completed over the period of May 2010 to November 2010. Learnings were grouped under key themes including communication, task organization and prioritization, stakeholder engagement, and emerging issues. conclusions: Developing a comprehensive plan to address obesity across the care continuum is a challenging but worthwhile process. Learnings can be applied to improve further planning for obesity as well as other provincial planning projects with strong linkages to obesity.

Eccentric Ergometer Training Promotes Locomotor Muscle Strength but Not Mitochondrial Adaptation in Patients with Severe Chronic Obstructive Pulmonary Disease

Eccentric ergometer training (EET) is increasingly being proposed as a therapeutic strategy to improve skeletal muscle strength in various cardiorespiratory diseases, due to the principle that lengthening muscle actions lead to high force-generating capacity at low cardiopulmonary load. One clinical population that may particularly benefit from this strategy is chronic obstructive pulmonary disease (COPD), as ventilatory constraints and locomotor muscle dysfunction often limit efficacy of conventional exercise rehabilitation in patients with severe disease. While the feasibility of EET for COPD has been established, the nature and extent of adaptation within COPD muscle is unknown. The aim of this study was therefore to characterize the locomotor muscle adaptations to EET in patients with severe COPD, and compare them with adaptations gained through conventional concentric ergometer training (CET). Male patients were randomized to either EET (n = 8) or CET (n = 7) for 10 weeks and matched for heart rate intensity. EET patients trained on average at a workload that was three times that of CET, at a lower perception of leg fatigue and dyspnea. EET led to increases in isometric peak strength and relative thigh mass (p < 0.01) whereas CET had no such effect. However, EET did not result in fiber hypertrophy, as morphometric analysis of muscle biopsies showed no increase in mean fiber cross-sectional area (p = 0.82), with variability in the direction and magnitude of fiber-type responses (20% increase in Type 1, p = 0.18; 4% decrease in Type 2a, p = 0.37) compared to CET (26% increase in Type 1, p = 0.04; 15% increase in Type 2a, p = 0.09). EET had no impact on mitochondrial adaptation, as revealed by lack of change in markers of mitochondrial biogenesis, content and respiration, which contrasted to improvements (p < 0.05) within CET muscle. While future study is needed to more definitively determine the effects of EET on fiber hypertrophy and associated underlying molecular signaling pathways in COPD locomotor muscle, our findings promote the implementation of this strategy to improve muscle strength. Furthermore, contrasting mitochondrial adaptations suggest evaluation of a sequential paradigm of eccentric followed by concentric cycling as a means of augmenting the training response and attenuating skeletal muscle dysfunction in patients with advanced COPD.

The Potential Role of Objective Activity Monitoring in Off-Site Follow-Ups Post-Bariatric Surgery

Title: The Potential Role of Objective Activity Monitoring in Off-Site Follow-Ups Post-Bariatric Surgery. Background: Weight gain and attendance at follow-up visits after bariatric surgery are of great concern for the multidisciplinary care team. Geography and schedules make attending follow-up visits increasingly difficult as time after surgery goes on. Recently, inexpensive commercially available activity monitors have become more common place, making information concerning physical activity and sedentary behaviours deliverable online, allowing for important patient lifestyle information to be transmitted to the multidisciplinary care team. The purpose of this study was to determine if off-site objectively monitored physical activity and sedentary time can describe health measures such as total body fat, abdominal adipose tissue (AAT), and weight maintenance long-term post-bariatric surgery. Methods and findings: 59 individuals who had undergone bariatric surgery wore an ActivPAL for seven consecutive days, monitoring physical activity and sedentary time and underwent one DXA scan to determine body composition. Linear regression shows that (moderate-to-vigorous physical activity (MVPA) explained 18.8% of variance in body fat (p=0.019) and 11.3% of the variance in AAT (p=0.033). Conclusions: Objective monitoring could offer beneficial information concerning patients’ health at post-surgical follow-up visits.